A caulking joint (hose joint) as being a piping member is used for a transfer of a fluid, such as oil used for hydraulic machinery (refer to, for example, Patent Documents 1 to 4). The caulking joint used for the hydraulic machinery is often manufactured by caulking in eight directions with the use of a caulking tool provided with caulking dies.
Meanwhile the fluid passes through a pipe used for the hydraulic machinery or the like at high pressure, and therefore the caulking joint is also subjected to the high pressure. When manufacturing a caulking joint for high pressure that is durable under the high pressure, in order to inhibit leakage of the fluid or the like, it is necessary to ensure that a caulking width is increased by caulking over a wide range and a caulking rate is enhanced by tight caulking.
However, when caulking under the above conditions by using a conventional caulking tool, there has been the problem that a nipple as a component for sealing the fluid and inhibiting hose slippage is susceptible to deformation (buckling), thus leading to deterioration of physical properties of the joint, such as sealing properties.